1. What is Water Deficit Calculation?

Water deficit calculation in pediatrics estimates the amount of free water needed to correct hypernatremia. It helps guide fluid replacement therapy in children with dehydration and electrolyte imbalances.

2. How Does the Calculator Work?

The calculator uses the water deficit formula:

Where:

• \( TBW \) — Total Body Water (liters)
• \( Na \) — Serum Sodium concentration (mmol/L)
• 140 — Target Sodium concentration (mmol/L)

Explanation: The formula calculates the volume of free water required to normalize serum sodium levels to 140 mmol/L in pediatric patients.

3. Importance of Water Deficit Calculation

Details: Accurate water deficit calculation is crucial for proper management of hypernatremic dehydration in children, helping to prevent complications from overly rapid or slow correction of sodium levels.

4. Using the Calculator

Tips: Enter total body water in liters and current sodium level in mmol/L. All values must be valid positive numbers. The result represents the estimated water deficit in liters.

5. Frequently Asked Questions (FAQ)

Q1: What is the normal range for serum sodium?
A: Normal serum sodium levels range from 135-145 mmol/L in children and adults.

Q2: How is total body water estimated in children?
A: Total body water varies by age and weight. In infants, TBW is about 75-80% of body weight, decreasing to 60-65% in older children.

Q3: How quickly should water deficit be corrected?
A: Sodium correction should be gradual, typically not exceeding 0.5 mmol/L per hour to avoid cerebral edema.

Q4: Are there limitations to this calculation?
A: This formula provides an estimate and should be used alongside clinical assessment. Ongoing losses and other factors may require adjustment.

Q5: When is this calculation most useful?
A: Primarily used for hypernatremic dehydration management in pediatric patients with sodium levels above 145 mmol/L.